Secretary of State Marco Rubio has ordered diplomats overseas to scrutinize the social media content of some applicants for student and other types of visas, in an effort to ban those suspected of criticizing the United States and Israel from entering the country, U.S. officials say.

Mr. Rubio laid out the instructions in a long cable sent to diplomatic missions on March 25.

The move came nine weeks after President Trump signed executive orders to start a campaign to deport some foreign citizens, including those who might have “hostile attitudes” toward American “citizens, culture, government, institutions or founding principles.”

Mr. Trump also issued an executive order to begin a crackdown on what he calls antisemitism, which includes deporting foreign students who have taken part in campus protests against Israel’s war in Gaza.

Mr. Rubio’s directive said that starting immediately, consular officers must refer certain student and exchange visitor visa applicants to the “fraud prevention unit” for a “mandatory social media check,” according to two American officials with knowledge of the cable.

The fraud prevention unit of an embassy’s or consulate’s section for consular affairs, which issues the visas, helps screen applicants.

The cable described the broad parameters that diplomats should use to judge whether to deny a visa. It cited remarks that Mr. Rubio made in an interview with CBS News on March 16: “We don’t want people in our country that are going to be committing crimes and undermining our national security or the public safety,” he said. “It’s that simple, especially people that are here as guests. That is what a visa is.”